Aircraft data communications services for users

ABSTRACT

A method and system provide efficient, flexible, and convenient data communication services for users over public wireless systems. The system includes a data communication server, having a plurality of interface units, for facilitating data communication between a moving object and one or more ground terminals via a radio communication path. The data communication server establishes the radio communication path over one of a plurality of wireless data networks including packet data networks and satellite data networks and preferably includes a pre-determined software architecture.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a division of application Ser. No. 09/884,724 filed Jun. 192001, now U.S. Pat. No. 7,177,939 B2, which is a continuation-in-part ofapplication Ser. No. 09/312,011 filed May 14, 1999, now U.S. Pat. No.6,760,778 B1. This application is related to U.S. application Ser. No.09/884,730 filed Jun. 19, 2001. Ser. Nos. 09/884,724 and 09/884,730 areco-pending and commonly assigned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to wireless data communicationservices. It particularly relates to aircraft data communicationservices for users.

2. Background

Existing data communication services, particularly for aircraft systems,are generally limited to particular applications. These particularapplications provided by non-public communication systems include groundflight recorder development, air traffic control operations, maintenanceoperations, position monitoring (e.g., global position satellitesystems—GPS systems), collision avoidance, aircraft surveillance,weather radar, in-flight entertainment and other specific applications.

Existing data communication services for aircraft passengers aresimilarly limited to particular communication protocols andsoftware/hardware systems, therein limiting convenience, affordability,and efficiency. These user communication protocols and systems includethe Terrestrial Flight Telephone System (TFTS) and other privatecommunication protocols and systems. These private systems requirespecialized, high-cost antenna equipment and power control systems or aninconvenient, invasive passenger ID assignment system to make use ofpublic communication systems such as the cellular communication systemor the public switched telephone network (PSTN), or requirehigh-interference systems such as the existing amplitude modulation (AM)aircraft communication systems. Based on these existing limitations ofnon-public communication systems, a need exists to enable flexible,seamless data communication for aircraft systems using public wirelessnetworks to increase affordability and efficiency.

SUMMARY OF THE INVENTION

The previously mentioned disadvantages are overcome by providing anefficient, flexible, and convenient method and system for providing datacommunication services for users. In accordance with embodiments of thepresent invention, a data communication server, including a plurality ofinterface units, facilitates data communication between a moving objectand one or more ground terminals via a radio communication path. Thedata communication server establishes the radio communication path overone of a plurality of wireless data networks including terrestrial andsatellite data networks and may include an object-oriented softwarearchitecture. Additional features of the present invention includepersonal data communication services for users and operational dataservices for the moving object.

Additional features of the present invention include a system forproviding communication services including a data communication server,co-located with a moving object, for establishing a radio communicationpath between a moving object and a ground station, the datacommunication server including software architecture including softwarefunctional layers, the layers including a system resources layer, asystem services layer, an application programming interface layer, andan application layer.

Further features of the present invention include a method of providingwireless data communication services including establishing a radiocommunication path between a moving object and a ground station using acommunication server co-located with the moving object, the datacommunication server including software architecture including softwarefunctional layers, the layers including a system resources layer, asystem services layer, an application programming interface layer, andan application layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a communication system architecture inaccordance with an embodiment of the present invention.

FIG. 2 is a block diagram of an alternative communication systemarchitecture in accordance with an embodiment of the present invention.

FIG. 3 is a block diagram showing the data link options in accordancewith an embodiment of the present invention.

FIG. 4 is a block diagram showing the data link options via a satellitenetwork in accordance with an embodiment of the present invention.

FIG. 5 is a block diagram of a communication system architecture using asatellite network in accordance with an embodiment of the presentinvention.

FIG. 6 is a block diagram of an alternative communication systemarchitecture using a satellite network in accordance with an embodimentof the present invention.

FIG. 7 is a block diagram of another alternative communication systemarchitecture in accordance with an embodiment of the present invention.

FIG. 8 is a block diagram of another alternative communication systemarchitecture in accordance with an embodiment of the present invention.

FIG. 9 is a block diagram of another alternative communication systemarchitecture in accordance with an embodiment of the present invention.

FIG. 10 is a block diagram of another alternative communication systemarchitecture in accordance with an embodiment of the present invention.

FIG. 11 is a call flow process diagram of a communication systemarchitecture in accordance with an embodiment of the present invention.

FIG. 12 is a block diagram of the software infrastructure for the datacommunication server in accordance with an embodiment of the presentinvention.

FIG. 13 is a software function layer diagram of a communication softwareinfrastructure for the data communication server in accordance with anembodiment of the present invention.

FIG. 14 is a block diagram for the service logic architecture of acommunication software infrastructure for the data communication serverin accordance with an embodiment of the present invention.

FIG. 15 is an application software function layer diagram of acommunication software infrastructure for the data communication serverin accordance with an embodiment of the present invention.

FIG. 16 is a block diagram of an alternative software infrastructure forthe data communication server in accordance with an embodiment of thepresent invention.

FIG. 17 is a property table of a communication software infrastructurefor the data communication server in accordance with an embodiment ofthe present invention.

FIG. 18 is an alternative property table of a communication softwareinfrastructure for the data communication server in accordance with anembodiment of the present invention.

FIG. 19 is an alternative property table of a communication softwareinfrastructure for the data communication server in accordance with anembodiment of the present invention.

FIG. 20 is a method table of a communication software infrastructure forthe data communication server in accordance with an embodiment of thepresent invention.

FIG. 21 is an alternative method table of a communication softwareinfrastructure for the data communication server in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION

System Components

FIG. 1 illustrates a representative data communication systemarchitecture 100 in accordance with embodiments of the presentinvention. The system 100 includes an aircraft data server 110, cabindistribution system (CDS) 150, and bearer services systems components180. The server 110 may be used as the main processor unit that providesprogrammable control over the routing, scheduling, and use of the system100.

The CDS 150 provides access to the data services provided by the system100 via the server 110. The CDS may include a plurality of componentsincluding a Human Interface Module (HIM) 155, a Passenger Access Server(PAS) or Terminal Server (TS) (not shown), and other components known tothose of skill in the art for forming a Cabin Communications System(CCS). The HIMs 155 may be laptop computers with applications forlogging data and interfacing with the server for data transfers. ThePAS/TS, which may advantageously be a part of the server 110 or anexternal device, can provide dial-up connectivity to the passenger seatsfor data service access.

The bearer systems 180 can provide the server 110 with the dataconnectivity to a plurality of ground-based servers. The bearer systems180 may include a plurality of components including an AirborneCommunications Unit (ACU) 205, a Wireless Gate-link system (WGS) 182, aSatellite Data Unit (SDU) 195, and a Terrestrial Flight Telephone system(TFTS) 200. The WGS 182 may be, for example, a wireless LAN transceiver(as shown in FIG. 1) based on the IEEE 802.11 specifications which canallow transfer of high-speed data to the server 110 in the airport whenthe aircraft (moving object) is on the ground. The ACU may act as thegateway to a ground-based data center via the North American TerrestrialSystem (NATS) network. Although the present invention is described withreference to the NATS network, the NATS network is solely exemplary andalternative communication networks may be used for providingair-to-ground data communication services.

The SDU may provide access a Satellite Communications (SATCOM) SatelliteBearer Service. The TFTS is used to access the European land-linetelephone network.

System 100 may include a plurality of components to provide higher databandwidth and passenger access technology for facilitating dataapplications, examples being Internet Web browsing and email retrieval.These components include Direct Broadcast Service (DBS) satellitedecoder 152, passenger cabin dial-up access system 151, and the WGS 182.Other components of system 100 can help facilitate data communicationsover the existing NATS data network.

The server 110 may include a CPU (not shown) comprising, for example, anIntel Pentium Pro, or equivalent processor system. The CPU providesmultiple functions including, for example, interfacing variousapplications for data storage and retrieval and managing various datacommunications interfaces for data transfer to the ground-based servers.

The server 110 may include a plurality of interface units forinterconnecting to various data networks. These interface units maycomprise a plurality of discrete I/O boards or a single integratedboard. Alternatively, the server 110 may include commercialoff-the-shelf (COTS) network cards to provide data communicationsservices for the system 100.

The plurality of interface (I/O) units may include an Ethernet interfaceunit 115, modem 120, communications (COM) port 135, Integrated ServicesDigital Network (ISDN) Basic Rate Interface (BRI) port 130, Primary RateInterface (PRI) port 125, ARINC-429 (Aeronautical Radio, Inc.) businterface unit 145, and ARINC-573 bus interface unit 140. The Ethernetunit 115 may include ports for interconnection to the HIMs 155 and tothe external terminal station (TS), and may be used to connect to thewireless local area network (LAN) transceiver 182 providing a high-speeddata path to ground terminals while the aircraft (moving object) is onthe ground. Alternatively, a COTS Ethernet card attaching to an externalhub (not shown) may be used.

The modem 120 and COM port 135 are used to enable the server 110 toprovide dial-up connection to the ground-based servers via the NATSnetwork. Additionally, in the packet data mode for system 100, the COMport 135 can be used to connect the server 110 to the ACU 205 directly.

The PRI port 125 and BRI port 130 allow users (passengers) to establishdial-up internet protocol (IP) connections, via the CDS 150, when thesystem 100 offers Web browsing, email retrieval, and otherpassenger-related data services. The BRI port 130 may also be used asone of the system 100 link options when operated in the packet datamode. This mode is entered when a call is established between the server110 and the ACU 205, and the bearer channel (B-channel) is operated in64-Kbps unrestricted mode. Once the call setup is completed, data istransferred without alteration allowing data-link protocols, an examplebeing Point-to-Point Protocol (PPP, RFC-1548), to be used to encapsulatethe IP packets sent to and from the ACU. This mode may also be referredto as the transparent bearer service.

The ARINC-429 bus interface 145 can be used by the server 110 to receivedata from a plurality of on-board management systems and to allow accessto an additional bearer service via the existing Aircraft CommunicationsAddressing and Reporting System (ACARS) messaging capabilities orSatellite Data Unit (SDU) if so chosen. The server 110 can also receivedata transmitted from the ground via ACARS using the interface 145.Advantageously, the interface 145 has at least one transmit port tointerface with an ACARS mobile unit (MU) 210 and at least two receiveports, one to receive management data from the Aircraft ConditionMonitoring Systems (ACMS) and one to receive data from the ACARS.Additional receiving ports can be added as need to provide furthermanagement applications to monitor data from on-board sensors via theARINC-429 bus interface 145.

Additionally, the system 100 may include a digital satellite system(DSS) interface unit (not shown) to provide broadband packet dataservice at faster rates than an T1/E1 rate. The broadband data servicecan use a Direct Broadcast Satellite (DBS) to transmit and receivepacket data, including a DSS channel coding scheme, quadrature phaseshift keying (QPSK) modulation and R-S forward error correction, MPEG-2technology for compressing and transporting (data link layer) thedigital video data, and low-profile antenna and DSS decoder PC board/boxto receive and decode the DSS signal. Other broadband methodologies mayinclude, but are not limited to MPEG-4 (e.g, H.263, H.261) and othercompression techniques including compression techniques that arestandards compliant or proprietary.

The ACU 205 enables air-to-ground communication using the existing NATSnetwork. Advantageously, two types of ACU can be used based on the typeof interface to the CDS 150, examples being a type 496 and a type4300/8600. Type 496 has 12 ISDN BRI ports that support direct interfaceto BRI handsets, and type 4300/8600 interfaces to the CDS 150 byconnecting to the Cabin Telecommunications Unit (CTU) 161 via ISDN PRIport 125. The data link to the ACU 205 may be via one of the B channelson the same PRI that carries voice traffic to the ACU 205 requiring theserver 110 to request a B-channel call to the ACU 205 via the CTU 161.

Both types of ACU can include a baseband unit (BBU), radio frequencyunit (RFU), and a power supply unit (PSU). The BBU advantageouslycontrols the data link connection from the aircraft to the nearestground station. Both types of ACU will accept two different data linkconnection types from the server. In the non-packet data mode, anasynchronous (Async) voice-grade modem dial-up via a B-channel ISDN linkusing a data access unit (DAU) 202 can be used. In the packet data mode,a transparent B-channel data link can be used.

In the non-packet data mode, the link operates with the BBU having aninternal modem to provide V.32/V.22 capability interfacing with themodem on the server 110. In the packet data mode, the server 110 canfirst encapsulate the IP packet in a PPP data frame and send it to theBBU using the clear B channel data service. Once the BBU receives thePPP frame, the BBU will strip off the PPP header from the PPP packet,and repackage the remaining IP packets into the radio (RF) framingstructure. The server 110 then modulates the data with phase shiftkeying (PSK) and up-converts the signal to radio frequency for the RFUto transmit to the ground. The RFU provides needed signal amplificationfor transmitted and received signals, and the PSU provides directcurrent (DC) power derived from the aircraft (moving object) powersource.

The Human Interface Modules (HIMs) 155 can be laptop PCs, for example,used by crew and operational personnel as the gateway to the systemapplications via a standard graphical user interface (GUI). HIMs 155 canbe housed, for example, in an adapter shell that allows connection to acommon docking station, the adapter shell providing the interfacebetween the HIM 155 and the docking station and equipped with anEthernet interface to connect to the server 110.

System Data Link Interface Options

The communication system, including server 110, has access toground-based data servers via several data bearer services asillustrated in FIG. 2. These data bearer services can include wirelessLAN services 250, NATS packet or voice-band data services 255, satellitedata services 265, terrestrial flight telephone services (TFTS) 270, anddirect satellite system services (DSS) 275.

FIG. 3 illustrates the data link options for the server and for theground-based customer premises equipment (CPE) using the NATS network.Advantageously, there are three data link options for the server 325 toconnect to the ACU for providing data communication services to theground. The first option is establishing a point-to-point protocol (PPP)connection 310 between the server 325 and the CPE 492 via a voice-gradedial-up over the existing NATS voice network. Other components of thedata link may include a data access unit (DAU) 340, ACU 370, groundstation 400, public switched telephone network (PSTN) 430, 480, andground data gateway (GDG) 465. The system can use PPP as the end-to-endlink layer protocol as if a direct connection exists between the serverand the CPE.

The other two options operate in the packet data mode. A regular trafficchannel of the NATS network will be used to carry the packetized dataand a circuit switch call is performed to maintain the channel for theduration of the packet transfer. The first packet mode option 310 usesthe ISDN BRI interface unit of the server 325 by connecting the server325 to the type 496-BBU, part of ACU 370, via the BRI line. To establisha radio communication path, the server 325 can send a call setup requestmessage to the 496-BBU, and the 496-BBU can request the ground stationfor a traffic channel before the 496-BBU establishes the call with theserver 325. After a channel is allocated, the 496-BBU returns acall-establish-message back to the server 325, and an end-to-end ISDNdata call is established between the server 325 and the 496-BBU.Subsequently, IP packets are transferred using the B channel byencapsulating them inside the PPP frame.

The second packet data option 305 uses ACU 370 of type 4300/8600. Inthis option, the server 325 is connected to the 4300/8600-BBU via theCTU 350 using the ISDN E1 PRI link. The call setup then follows asimilar scenario as to the first packet data option that used BRI exceptthat the CTU 350 is used to establish the call to the BBU, part of ACU370, over one of the B-channels. At the BBU, IP data packets are channelencoded and encapsulated in radio frequency (RF) data frames.Subsequently, the data packets are modulated onto a radio frequency andsent to the Ground Station (GS) 400. At the GS 400, the data packets aresent along to the Ground Data Gateway (GDG) 465 via a Frame Relay (FR)network. The GDG 465 advantageously transfers the IP packets todifferent networks by proper protocol conversions, and receives allground-to-air packet data call requests, sending them to the destinationair terminal via an associated GS where a radio link is established bythe air terminal.

Additionally, an alternative system architecture 330 can be used for apacket data mode allowing aggregation of multiple radio links to providehigher data throughput. This higher data rate can be achieved bytunneling the PPP frame from the server 325 to GDG 465 via a Layer TwoTunneling Protocol (L2TP). L2TP tunneling allows the PPP session to beinitiated by the server 325 and terminated at the GDG 465, not the BBU(part of ACU 370), allowing the server 325 and GDG 465 to establishmultiple PPP sessions over multiple radio links. The GDG 465 enables theserver 325 to negotiate a PPP Multilink Protocol (MP) with GDG to bundleall the PPP sessions together to form a higher bandwidth virtual pipe.

Tunneling (L2TP) provides a number of unique advantages for the system.These advantages include using the existing infrastructure to make theaddition of server data communication services transparent to theexisting Air-Ground network until the IP packet arrives at the GDG.Further advantages include the following: 1) lower development costsbecause development is only needed at the two ends, server and GDG, andthe existing serial line internet protocol (SLIP) on the BBU can be usedfor delivering L2TP packets; 2) allowing single point of processing forIP address assignment and packet filtering because only the GDG will beused to maintain databases; 3) allowing end-to-end recovery and flowcontrol which therefore removes the need for the BBU to performbuffering and link layer maintenance; 4) allowing aggregation ofmultiple radio links to increase throughput using MP; 5) allowing futuredevelopment of new PPP extensions without requiring changes to theBBU/GS because the radio network just passes the packets through the GS;6) enabling tunneling interfaces with other bearer services, allowingall communications to occur between the server and the GDG independentof the bearer service selected.

For the CPE 492, three data link options can be selected depending onthe type of data mode to be used. For a voice-grade data link, the CPE492 can interface to the system via a V-series modem connected to atwo-wire analog line from the LEC (local exchange carrier). For packetdata mode, the CPE 492 has two options. For a first packet data modeoption, the CPE 492 can use a frame relay service if the CPE is part ofan already existing frame network. Advantageously, a permanent virtualcircuit (PVC) from each GS to a NATS data gateway over the existingframe network can be established to deliver IP packets from the aircraft(moving object). The CPE can act as a router connecting to the systemwith the server behind it, or alternatively the server can terminate theframe relay service and IP is transmitted over the link. For the secondpacket data mode option which provides lower costs, ISDN BRI service isobtained from the local exchange carrier (LEC). When IP packets aredestined to the CPE, the GDG will set up the data link dynamically bycalling to the CPE using PPP for IP encapsulation.

An alternative bearer service used by the system can be a satellitecommunication service. One example can be the INMARSAT DATA3 serviceswhich provides an X.25 service with maximal data throughput (e.g., 10.5Kbps) and is accessible through the SDU 195. FIG. 4 shows the connectionoptions 500 for connecting the server to the SDU. Two options 510, 520may use an ISDN D-channel to establish the X.25 SVC (switched virtualcircuit) and transport the X.25 data packets. An alternative option 530can use the high-speed ARINC-429 port 145 to interface directly with theSDU for X.25 call setup and data transport.

Other alternative bearer services can be used including broadbandsatellite link services—for example, a DBS system. A suitable digitalcompression system, for example a Moving Picture Expert Group (MPEG-2)system, can be used to multiplex any digital signals with digitizedvideo signals, including any packet data, on to one or to a very smallnumber of satellite transponders. Other compression methodologies mayinclude, but are not limited to MPEG-4 (e.g, H.263, H.261) and othercompression techniques including compression techniques that arestandards compliant or proprietary.

Use of a DSS system/interface unit allows for broadband communicationindependent of the particular link content, either a compressed videosignal or a sequence of IP packets which can be deciphered by a videocoding device at the GS and the DSS receiver on the aircraft. Passengerand cabin applications for this broadband satellite service include, butare not limited to, software downloading, flight information updates,Internet browsing, and TV/video delivery.

FIG. 5 shows the architecture 600 of a satellite data communicationservice using DSS technology. The system architecture includes aircraftsystem 610 having server 615 and CTU 612 for facilitating acommunications link to a DBS data center 630, via a DBS Satellite 618,and NATS network 620 interconnected to internet facilities 640 and CPE650. DBS data center 630 includes router 638, satellite accessmanagement system 637, DSS encoder 636, and radio equipment includingcombiner/uplink 635. The system architecture 600 further includes on theaircraft a DSS receiver/decoder and antenna (not shown) to helpfacilitate the broadband service.

The system architecture 600, using asymmetrical data transport, canprovide large bandwidth (e.g., in excess of 5 Mbps) from the network(DSS, upstream) to the aircraft and from the aircraft to the network(e.g., 4.8-9.6 Kbps) (NATS, downstream). A large bandwidth for theupstream can be useful for web applications since most Internet browsingretrieves a much greater amount of information than is initiallytransmitted.

Alternatively, other satellite bearer services can be used to deliverdata communication services, for example, LEO/MEO/GEO (low earthorbiting/middle earth orbiting/geosynchronous earth orbiting) satellitesystems. Specific commercial examples of suitable LEO/MEO/GEO systemsinclude, but are not limited to Iridium, Globalstar, ICO, Odyssey,Millennium, Space, Astrolink, Cyberstar, and Teledesic. Use of thesesystems enables data service offerings in the exemplary range of 384Kbps-1.2 Gbps, and allows various data applications including videoconferencing, high-quality video, high-speed Internet, and virtual LANservice.

FIG. 6 shows a representative example of a data communication systemarchitecture 605 using a LEO/MEO/GEO satellite network. The systemarchitecture 605 includes aircraft 610 having CTU 612 and server 615,with a data communication link to satellite network 685 and groundnetworks 695 via satellites 680, 690. The ground networks 695 canadvantageously include GDG 694, video conference facility 691, VPN(virtual private network) 693, Internet facilities 640, and web server692. The aircraft 610 acts as one of the ground-based clients receivingand transmitting high speed data via the satellites 680, 690. The system605 is a two-way system which alleviates the need to use the NATSnetwork for a return path, and allows the server 615 to treat thesatellite link as just another two-way bearer service by using thesatellite broadband network 685 to interconnect the aircraft 610 and theground networks 695, via a mobile terminal (MT) (not shown) connectingto the ground networks 695.

The satellite network 685 can perform necessary routing and handoffprocedures to establish and maintain connectivity between the aircraft610 and ground networks 695. Additionally, the satellite network 685 canserve as a network cloud providing connectivity between any pair ofclients (e.g., aircraft 610 and ground networks 7695) preferably usingSVCs or PVCs.

The aircraft 610 includes a satellite transceiver unit capable oftransmitting and receiving data using any particular satellite network,and having the capability of handling either ATM or frame relay protocolsuch that a SVC or PVC can be established between the aircrafttransceiver box and ground networks 695. Using this setup, IP packetscan be encapsulated by these lower layer protocols to enable atransparent conduit for IP packets to travel from the aircraft to thedesired ground networks 695.

Another alternative data link option enables passenger cabin dial-upaccess services. FIG. 7 shows the communication system architecture 148for passenger cabin dial-up services. The system architecture 148includes cabin distribution system 150, server 110 having itscomponents, and can further include digital flight data acquisition unit(DFDAU) 710, ACARS MU 750, and other components.

The system 148 allows a user (passenger) to access internet service,either via an on-board internet service or using the server as a proxyto access the rest of the Internet. At least two types of access areavailable depending on the configuration of the user's access device(e.g., laptop). For all access scenarios, the connection to the server110 via the TS function will be over a CTU-switched ISDN B-Channel.Advantageously, the user's access device can be equipped with a PCMCIAV-series modem allowing connection to an RJ-11 jack on the handset, andthe handset can be connected to the CTU 152 via the CDS network. Forthis configuration, a modem pool, as part of the TS function, can peerwith the laptop modem, and the link layer protocol is PPP so that properauthentication (for billing purposes) and dynamic IP address assignmentcan be achieved. Advantageously, a useful COTS TS for serving thisfunction includes, but is not limited to, the Ascend MAX or US RoboticsTotal Control that, on one end, can interface with the CTU via a T1/E1PRI or with the BBU via a BRI and, on the other end, with the server viaEthernet (see FIG. 1)

Alternatively, the user's access device can be equipped with an ISDNmodem, alleviating the need for the server 110 to have modem capability.In this configuration, an internal COTS PRI PC card can be used forhandling the end-to-end digital signal. Advantageously, this particularconfiguration imposes no additional development on the aircraft end,only requiring modification on the handset to provide a U-interface forconnecting to the user access device ISDN modem.

Networking

FIG. 8 shows a more detailed illustration of the server data link optionto the ground using the existing voice-grade NATS network. This systemarchitecture 900 includes access device (e.g., laptop) 910, server 920,DAU 925, BBU 930, modem 937, and RFU 935 as part of the air portion ofthe architecture 900, and RFU 940, BBU 945, modem 955, switching center950, PSTN 960, and terminal server (TS) 965 as part of the groundportion of the architecture 900.

As described previously, a point-to-point link can be establishedbetween the aircraft and remote server using the PPP link layer protocolto encapsulate IP for transfer across this virtual connection. The datalink can be established in three stages, using an air-to-ground linkrequest, ground-to-ground call setup, and end-to-end call setup.

Advantageously, the air-to-ground link can be first requested using aFAX/DATA channel request signal via the DAU 925 to the BBU 930. BBU 930can determine which ground station to use and can then send a requestchannel signal, via RFU 935, to the ground station (GS) selected. Oncethe selected GS finds an available channel, the GS sends a request tothe switching center (SC) 950, receives an acknowledgment, and thenreturns the acknowledgment with the assigned channel to BBU 930, via BBU945 and RFU 940. After receiving the acknowledgment signal, BBU 930sends a signal to server 920 via DAU 925 indicating that a channel isbeing made available. Upon completion of this air-to-ground link request(channel availability), the voice path can be established between theserver 920 and the SC 950, and the SC 950 inserts an in-band dial-toneand waits for the server 920 to out-pulse in-band DTMF digits tocomplete the ground portion of the call connection.

Once the air-to-ground call setup is completed, the ground-to-groundcall setup can then proceed. Once the server 920 receives the “dial-now”signal, it then out-pulses the 10-digit phone number to the SC. The SCthen connects to the destination number via the PSTN and bridges the twoconference legs together. At this point, the SC returns the callprogress tone all the way back to the server 920. Upon answering thecall, the remote TS 965, either at the GDG or the CPE, sends the in-bandmodem answer tone, via modem 955, to start the modem negotiation withthe calling party, via modem 937. Once the GS detects the modem tone, itcuts the voice path, and sends a signal to the BBU 945 to request it tostart modem training with the server 920. At the same time, the GSstarts the modem training with the TS 965. When both pairs of modems937, 955 complete the training, the data can flow through the air linkusing a particular out-of-band protocol while the data flowing betweenthe two pairs of modems can use a V-series protocol.

Once the setup of the physical layer between the server 920 and TS 965is completed, the TS 965 can start the link layer negotiation with theserver using the PPP protocol in accordance with RFC 1548, 1549including the three main components of PPP: LCP (Link Control Protocol),NCP (Network Control Protocol), and multi-protocol encapsulation. PPPencapsulation frames can be used to carry the IP traffic across the datalink between the two PPP peers, the server 920 and the TS 965 of theground network. Advantageously, the server 920 may act as a proxy serveror perform network address translation for any clients on the same LAN.

FIG. 9 shows a more detailed illustration for the packet dataconnections using the NATS network. The link architecture 1000 includesserver 1005, CTU 1008, ACU 1010, GS 1015, GDG 1020, and CPE 1025.Different data link protocols can be followed over different linksegments. Advantageously, a call scenario can start when the server 1005needs to establish a data link to the ground IP network. When the BRI isused, the server will send out a call setup request via the D channel tothe BBU with data call indication. The BBU will then request a trafficchannel from the GS 1015 for data use. Once the GS allocates a channeland acknowledges the BBU, the BBU will send back the call connected Q931message back to the server 1005 and allocate the B channel for such use.All subsequent IP data will go over this clear B channel using PPP toframe the IP packets.

Alternatively, if the ISDN PRI is used instead for call setup, the callrequest can be initiated when the server sends a call setup message tothe CTU 1008 as described previously. CTU 1008, based on the destinationnumber of the call setup message, will send an incoming data callindication to the BBU. Once the BBU detects the incoming call event, itwill proceed and negotiate a traffic channel as described previously.Once the channel is allocated, the BBU will send back call answermessages to the CTU to inform the server 1005 that a data link is up andit is ready to receive any PPP packets. Once the PPP packet arrives atthe BBU, the BBU will strip off the PPP header from the PPP packet, putthe remaining PPP packets into RF frames, and transmit thechannel-encoded RF frames over the radio link to the GS 1015.

Once the GS 1015 receives the radio frame, it will recover the IP packetand forward it to the GDG 1020, advantageously serving as a router andinterface to the public Internet and to the private network thatinterconnects the CPE servers such that every IP packet will be routedto the appropriate network based on the destination IP address. Forground-to-air packet data calls, the GDG will send call request messagesto the associated GS for certain destination air terminals via a framerelay network. When a radio link is available, a connection will be setup from GDG to server (using circuit mode from GS to server).

Circuit Mode Data in the Packet Data Network

The packet data architecture described herein can be used for animproved circuit mode data solution (non-CTU installation). The circuitmode data system architecture 1100 is shown in FIG. 10. The systemarchitecture 1100 includes user access device (e.g., laptop) 1105,telephone 1110, ACU 1115, TS 1125, antenna 1120, radio tower 1135,server 1130, ground station controller (GSC) 1140, router 1145, framerelay 1150, router 1155, GDG 1160, modem pool 1156, PSTN 1170, anddestination modem 1175.

FIG. 11 illustrates the call flow procedures 1200 for the circuit modedata solution for the packet data network. In accordance withembodiments of the present invention, the circuit mode data solution canuse a TCP/IP interface to be constructed between the server and the GDG.The call flow 1200 includes a plurality of components including useraccess device (e.g., handset) 1205, TS 1210, server 1215, BBU 1220, GSC1225, GDG 1230, and remote end device 1235.

Upon user request from the user access device 1205, the BBU 1220 cancheck to verify that adequate radio and server resources are available.Assuming adequate resources are available, the BBU 1220 will thenproceed to reserve a modem on the TS 1210 and establish a link to theGSC 1225. Once the link to the ground is established, an end-to-end TCPcircuit is setup between the appropriate GDG 1230 and TS 1210components, advantageously performed using telnet or a socket connectionbetween the two components. The BBU 1220 also forwards dialing anddialed numbers to the GDG 1230. Pending a sanity check on the dialednumber and a validation check on the billing instrument, the GDG 1230will initiate a connection to the desired destination party via a modem.Simultaneously, the BBU 1220 will transfer the call to the TS 1210voice-band-data BRI interface with both modem connections (i.e.,passenger to TS 1210 and GDG 1230 to remote end device) negotiating thelink separately. Upon confirmation that these two links have beenestablished, the GDG 1230 and TS 1210 can shuttle information to eachother. Additionally, this configuration can support handoffs ofvoice-band-data calls.

Server Software Architecture

As illustrated in FIG. 12, the server of the data communication systemcan advantageously include an object-oriented software architecture1400. Software architecture 1400 includes server 1410, GDG 1430, andground-based servers 1440. An object-oriented software architecture isexemplary and alternative software architectures may be used including,but not limited to, C++, JAVA, HTML, etc.

Use of an object-oriented design includes that each system resource orservice provider bears an object entity, and that services areaccessible via the published methods. Resources are managed within theobjects. Additionally, the server 1410 may advantageously use aclient-server model wherein the clients request the service by accessingthe published methods or interfaces on the servers 1440. The softwarearchitecture also advantageously may use location transparency whereinthe objects are accessible by the clients universally within theconfines of the access control and the network connectivity.

As shown in FIG. 12, the software architecture 1400 may optionallyinclude GUI (Graphical User Interface) 1420 having interfaces allowingdata communication applications to request services from the server1410. Preferably, objects on server 1410 can advertise services thatapplications are allowed to access, the applications also accessing aStructured Query Language (SQL) manager as needed to interact with theGDG 1430 to retrieve or send data. The GDG 1430 may serve as a DataProxy, using local storage space to either cache the data for upload tothe server 1410 or download to the customers' (user) ground-basedservers (GBS) 1440. GDG 1430 will then use the proper transport tointeract with the GBS 1440 for data transfer. The GUI 1420 can beoptional to the design as applications may run unattended without humanintervention and therefore are only used for maintenance operationsunder those conditions. The design of the architecture 1400 isindependent of the underlying operating system.

The software architecture can be logically divided into four functionallayers 1500 as shown in FIG. 13. These layers include an applications(AP) layer 1505, application programming interface (API) layer 1510,system services (SS) layer 1515, and system resources (SR) layer 1520.The AP layer can contain applications that are developed by the aircraftor other parties. The SR layer contains the system resources that areused by the SS layer when providing service to higher layer components.The SR components can include the server bearer resources, thedatabases, the data storage, and JAVA execution environment, etc.

The SS layer components provide system-level services to the objects inthe API layer or to other components in the same layer. The services caninclude, but are not limited to, various TCP/IP services, avionicsstandards services, data compression and cryptographic services,scheduling, and transaction-oriented services. The SS layer includes APIadministration SS to manage all API objects, its purpose being toprovide access control, service activation/deactivation, and propertychange capabilities of the API object to the data communication serviceprovider.

Advantageously, the SR layer may include at least four types ofcomponents used by the data communication server. These components caninclude device drivers, BITE system, file system, and miscellaneousfacilities. Dependent on the underlying OS of the data communicationserver, the components of the SR layer may be part of the embedded OS ormay be specially designed for aircraft data communication services.

Device drive (DD) components enable the SS layer components to interactwith communication devices for data exchange with the GDG or withonboard avionics devices. Advantageously, the DD may be part of theunderlying OS or may be specially developed, and includes a plurality ofcomponents including a BRI driver, PRI driver, Ethernet driver,ARINC-429 driver, and ARINC-573 driver.

The SR file system can advantageously provide a consistent way to store(or provide permanent storage—persistence) the data, including allowingthe SS components to perform read, write, and delete operations based onparticularly developed user rights or permissions. Additionally, thefile system can include a special system file, the route table, used fordetermining the routing for IP packets. The route table can include aset of known routes and be locally stored in non-volatile memory.

Miscellaneous facilities can include an SQL database and a JAVA VirtualMachine (VM). The SQL database provides a database engine to store andmanage the data needed by the server SS and API components, includingall necessary database transactions such as query, insert, update, anddelete functions. Advantageously, the JAVA VM can allow the server toaccess other network-based services using JAVA applications or applets.Use of the VM allows the server to write an API using JAVA architecturethat allows clients from other platforms running a different OS torequest services from the data communication server with a standardizedprotocol.

The API layer provides a consistent way for the AP to acquire andutilize data-oriented aircraft services. Advantageously, a genericobject is produced, an example being the generic business object (BO),that will allow access to these services assuming specific transportprotocols (e.g., TCP/IP, UDP, etc.). This allows use of an objectwithout specific knowledge of the service support structure.Alternatively, each component in the API layer can be represented as anobject that provides one specific aircraft service, each objectcontaining three major parts—the communicator, the receptor, and theservice logic. Services provided by each API object can be characterizedby properties, methods, and events and are exposed through thecommunicator and the receptor.

The communicator is a client-side component which can be represented asa control in a user object (UO), or the object embedded in AP, whichenables the AP to invoke services and to communicate or share the dataconstruct with the object via a known set of properties, methods, andevents. The receptor component which can be represented as a control inthe business object and which resides inside the object itself, is usedto accept the service requests and to share and communicate back withthe AP. The service logic is the implementation of the object itself andhas access to the lower-layer components. This architecture isillustrated in FIG. 14 and comprises the client process 1605 and thelocal server process 1618. Client process 1605 includes clientapplication 1610 and user object 1615, and local server process 1618includes business object 1620 and local server 1625.

Other API objects can include Objects to retrieve updatable ortime-sensitive information for a user, information that may lose itsvalue if not retrieved by the user in a pre-determined period of time,and information that may be updated as a result of this value loss. Thisupdatable or time-sensitive information for the user may include newsinformation, sports scores, weather information, traffic information,politics information, business information, finance information, andother updatable or time-sensitive information. Other objects may includeFMS (Flight Management System) Object for database loading, the FOQA(Flight Operations Quality Assurance) object for obtaining and managingACMS data, and other objects.

In practical operation, the communicator can provide the clients thenecessary networking and protocol handling capability to executeservices on the server, and the receptor handles the requests initiatedby the clients and starts “Instances” of the services being requested.Following this process, the communicator of the API allows theapplications to make use of the services provided by the server.Similarly, the communicator of the SS object allows other SS and APIcomponents to utilize the services provided by the SS object.

FIG. 15 shows a representative example of the functional layer process1700 for an exemplary application, a sports score application. A similarprocess can be followed for other applications to retrieve updatableinformation. The functional layer process 1700 includes a plurality ofcomponents including client 1705, admin server 1710, file system SR1730, retriever SS 1715, BRI SR 1725, Database SS 1722, IP stack SS1735, and GDG 1720.

For this example, a sports score retrieval SS 1715 is advantageouslyregistered with the scheduler enabling execution periodically toretrieve sports scores from the GDG 1720. A sports scores admin server1710 instantiates sports scores API objects 1712 and makes themavailable for the sports score clients 1705 to obtain sports scores forthe user. A Database SS 1722 is used by sports scores API 1712 andretriever 1715 to store (persist) and share the scores files,advantageously stored in a user profile. It is also used by theretriever 1715 to initiate an SQL query, via the IP Stack SS 1735 andBRI SR 1725 (or alternatively, an Ethernet SR), to the GDG 1720 toretrieve the latest cached scores.

FIG. 16 illustrates an exemplary configuration for the softwarearchitecture 1800 for an end-to-end system between the cockpit and cabinterminals 1870, airborne data server 1875, and ground data gateway 1880.

The sports scores admin server 1710 allows a system administrator toperform a plurality of functions including starting/terminating thesports scores service, changing the property of each active instance andthe default property of the service, changing the automatic updateschedule using the sports scores retriever 1715 control, and initiatingan on-demand update using the sports scores retriever 1715 control.Additionally, the admin server 1710 maintains the database that containsall the sports scores records wherein advantageously the client API canbe allowed access to database records with “read” permission only, andboth the admin server 1710 and the retriever 1715 have full control overthe records.

The sports scores retriever 1715 advantageously can have access to boththe sports scores database and the sports scores locator database. Theretriever 1715 can use the information in the locator database toconstruct the SQL queries, such as the token representing the recordsdesired, the SQL server location, and the property of the records, andother information to retrieve the sports scores records. The retrievedinformation will be written to the sports scores database, and a properevent will be sent back, either to the client 1705 or the admin server1710, to inform the availability of the updated records. Additionally, aGUI will be available to a system administrator to perform a pluralityof functions including initiating a complete on-demand update,initiating a partial on-demand update based on the client propertyforwarded, allowing modifications to the automatic update schedule, andchanging the locator database records.

FIGS. 17-19 provides a representative example of the administration,client, and retriever control properties of the server control part ofthe API categorized by property name, type, allowable value, andcomment.

In practical operation, the client requests services via methods.Advantageously, a generic method may be created but with differentproperties to differentiate various services requests, or differentmethods may be created to represent different requests. FIGS. 20-21provides a representative example of the different server-side andclient-side methods that can be created for the sports scores API.

Additionally, clients can request an object to send notification in casea specific event has occurred. Advantageously, the client is notified ofan event in the form of executing the call event function on the clientside. For the exemplary sports scores API, there are two events that canbe required, one for indicating the successful completion of “method”execution, and another for indicating when the “method” executionfailed. Optionally, an error code may be used as part of the event toindicate the cause of the failure.

Referring again to FIGS. 15, 17-21, an illustrative example of howsports scores AP invokes the data communication server's sports scoresservice and the actions performed as characterized by properties andmethods are shown.

Initially, for the “client requests for scores” action 1706, the usercan select the desired options on the property menu via the GUI anddemand an unconditional update (see FIG. 22). Then, for the “serverretrieves data requested” action 1707, the server-side Sports Scores API1712 reviews the client-controlled property (see FIG. 19) and initiatesan SQL query of the sports scores table via the SQL Manager SS to verifythat data is up-to-date. For this example, the SQL query suggest thatthe data requested is out-of-date. Next, in the “server requests forupdates” action 1708, the server-side sports scores API 1712 demands anupdate (see FIG. 21) which invokes the sports scores retriever SS server1715 control using the retriever control property (see FIG. 20). Then,for the “retriever initiates SQL-based scores retrieval” action 1709,the sports scores retriever SS component 1715 invokes SQL Managercontrol to query the sports scores locator records for detailedinstructions to initiate an SQL-based data query (e.g., SQL script ID).Then, the retriever 1715 instructs the SQL Manager to retrieve therequired data records. Then, for the “low-level SQL queries andretrieval” action 1711, the SQL Manager initiates queries byestablishing an SQL port, TCP or UDP, connection to the SQL serverinside the GDG 1720.

The request can be wrapped by the IP Stack SS 1735 and can be sent tothe proper BRI SR 1725 that has the connection to the desired bearer viathe routing table lookup. The SQL query requests that an IP packet bedelivered to the GDG 1720 where corresponding TCP/UDP ports are beingused for accepting the SQL connections. Advantageously, the SQL serveron the GDG 1720 returns the results of the query back to the database SS1722. The sports scores retriever 1715 receives an event notification ofthe completion of the query.

For the “sports scores retriever notifies server of task completion”action 1713, the sports scores retriever sends a completion event to theServer by executing a call-back function. Then, for the “server readsdatabase records” action 1714, the server API, embedded as part of thecall back function, contacts the database manager for the requestedsports scores wherein the retrieved data is delivered to the client sidesports scores API object 1705. Then, for the “client reads scores”action 1716, the client-side API 1705 receives the completion event andretrieves the data delivered by the server-side API 1712 wherein theresults (updated sports scores) are presented to the user via the clientGUI controls.

Applications

Several applications are enabled by the data communications systemarchitecture including aircraft operations applications, cabinapplications for aircraft personnel, and passenger applications.Advantageously, many of the applications use a display observable to theaircraft crew or passenger to display requested or automaticallygenerated information (e.g., catalog of products or services) via thedata communication server, and provides for delivering information(e.g., credit card) to facilitate a purchase. Operations applicationsare intended to increase the operational efficiency of the airlineflight crew, flight operations, department, and/or maintenancedepartment in the operation and maintainability of the aircraft.Operations applications can include, but are not limited to, electroniclibrary systems (ELS)/electronic logbook, flight operations qualityassurance (FOQA), engine data, performance reports (V1 speeds, rotationangle), aircraft position, out, off, on, in (OOOI)/flight phase reports,and data loader. Further operations applications may include aircraftcondition monitoring system, fault reports, gate assignment, weightdata, departure reports/pre-flight briefings, clock synchronization,delay reports, gate requests, ACARS, crew scheduling, and weather.

The ELS/electronic logbook provides a paperless environment for theaircraft crew to manage aircraft operations. The system includesreference to on-line manuals and guides and provides an electronicmechanism for items requiring logbook entry. Logbook entries can beautomatically sent to the aircraft operations center for an updated copyof the logbook system, this copy serving as a backup to the electroniccopy kept on the aircraft system.

FOQA is an FAA-sponsored program to increase aircraft flight safety viamonitoring aircraft and pilot performance through the various datasupplied by the aircraft sub-systems. The data can be stored on-boardthe aircraft and delivered at a later date to aircraft flight operationsor can be delivered real-time via the data communications server. Theengine data application can include real-time delivery of engineperformance data to the aircraft operations center, obtainable via theACARS MU or via the ARINC-429 bus connected to an engine electroniccontroller (EEC). Performance reports may include monitoring of pilotactions during critical phases of flight such as takeoff and landing toprovide the flight operations input for corrective actions in trainingprograms or technical literature. Additionally, data analysis used tomaximize flight performance may include monitoring of such data asactual vs. calculated V1 speeds, angle of rotation, flap deployment, andangle of ascent/descent.

Real-time aircraft position is used by the aircraft operations center totrack the aircraft and provide real-time feedback for performancemonitoring and route adjustments to pilots. Advantageously, the datacommunications server may obtain position information from an on-boardpositioning system (e.g., global positioning satellite) and route thatinformation to the aircraft operations center. Other applications usethe data communication server to provide the requested data.

Cabin applications can be advantageously intended to increase theoperational efficiency of the aircraft cabin crew and/or maintenancecrew. Cabin applications can be also intended to provide new passengerservices or more efficient use of existing passenger services. Cabinapplications can include, but are not limited to, connecting gates/delayreports, duty-free shopping (allowing aircraft personnel to validatecredit purchases of duty-free goods via a card reader), frequentflyer/customer profile, on-board inventory, systems information andtroubleshooting, departure reports/pre-flight briefings, FAcommunication system, flight attendant comments tracking system (FACTS),email, cabin discrepancy log (CDL), catering reports (allowing userpre-selected catering services), and baggage/asset tracking.Baggage/asset tracking can be advantageously implemented using the datacommunication server in combination with an RFID tag system (e.g.,integrated into baggage tags) to track and locate aircraft baggage andassets. The RFID tags could be read with RF readers for tracking andidentifying of baggage and assets, including a data link (e.g.,Ethernet) to the data communication server for processing.

Passenger applications are intended to provide a more comfortable,convenient aircraft experience for the passenger (user). Passengerapplications can advantageously include, but are not limited to,transaction processing, sports scores as described herein, connectinggates/delay reports, service selections, reservation system access,messaging service, marketing tracking, surveys/comments, shopping,email, advertising, on-line services as described herein, passengerinflight information (PII), GTA registration for telephony services, andmedical information.

Although the invention is described herein using the NATS network as aprimary bearer service for an aircraft data communication service, itwill be appreciated by those skilled in the art that modifications andchanges may be made without departing from the spirit and scope of thepresent invention. As such, the method and apparatus described hereinmay be equally applied to any bearer service providing datacommunication services for a user from any moving object.

1. A method of providing wireless data communication service between amoving object having a communication server embodying a softwarearchitecture and a first ground station, wherein the softwarearchitecture includes a plurality of software functional layerscomprising an applications layer, an application programming interfacelayer, a systems services layer, and a system resources layer, themethod comprising: establishing a radio communication path via systemresources layer components that communicate with systems services layercomponents, the system resources layer components including a devicedriver for data exchange, between the moving object and a first groundstation, wherein the system services layer components provide systemlevel services to objects of the application programming interfacelayer; establishing a connection between the first ground station and asecond ground station; transmitting data including operational data ofthe moving object using system services layer components from the movingobject to the first ground station via the radio communication path, andtransmitting data from the first ground station to the second groundstation via the connection between the first ground station and thesecond ground station.
 2. The method of claim 1, wherein the connectionbetween the first ground station and the second ground station is formedat least in part by the PSTN.
 3. The method of claim 1, furthercomprising establishing an end-to-end link layer connection between thecommunication server and a terminal node.
 4. The method of claim 1,wherein data packets are modulated onto a radio frequency and sent tothe first ground station via the radio communication path.
 5. The methodof claim 4, wherein the data packets are sent from the first groundstation to the second ground station via a frame relay network.
 6. Themethod of claim 1, wherein a point-to-point protocol frame is tunneledfrom the communication server to the second ground station via a LayerTwo Tunneling Protocol.
 7. The method of claim 1, comprising:communicating via components of the system resources layer with thesystems services layer components; exchanging services data with thefirst ground station via a device driver included as a component in thesystem resources layer; and via the system services layer components,the first ground station and the second ground station, communicatingservices data regarding at least one of avionics standards services,data compression and cryptographic services, and onboard avionics by wayof the device driver.
 8. A method comprising: from an aircraftcommunications server, transmitting data packets including data packetscontaining data related to operational data of the aircraft from anapplication of an applications layer of a software architectureimplemented on the aircraft communications server according to apoint-to-point protocol to a ground-based network, wherein thetransmitting comprises transmission via multiple radio links, andwherein a point-to-point protocol frame is tunneled from the aircraftcommunications server to a ground data gateway via a tunnelingprotocol,; and receiving data packets at the aircraft communicationsserver via a satellite uplink according to access controls provided bysystem services layer components according to the software architecture,wherein the system services layer components exchange data with onboardaircraft avionics using a device driver.
 9. The method of claim 8,wherein the ground-based network includes a NATS (North AmericanTerrestrial System) network.
 10. The method of claim 8, wherein theground-based network includes the Internet.
 11. The method of claim 8,wherein the aircraft communications server includes object-orientedsoftware.
 12. A communications system comprising: a communicationsserver located on an aircraft, the communications server including aninterface to establish a point-to-point protocol communication path atleast in part via a radio link to at least one ground station; and asoftware architecture embodied on and executed on the communicationsserver including a plurality of software functional layers andcomponents to support data communication including communicating datarelated to onboard aircraft avionics, via the communication pathincluding in part a radio link to at least one ground station, whereinthe software functional layers include an applications layer, a systemsservices layer, and a system resources layer, wherein system resourceslayer components communicate with systems services layer components, thesystem services layer components providing services including at leastone of avionics standards services, data compression and cryptographicservices, and wherein the software functional layers further comprise:an application programming interface layer including objectscorresponding to aircraft services, wherein the system services layercomponents provide system level services to the objects of theapplication programming interface layer.
 13. The communications systemof claim 12, wherein the software architecture includes object-orientedsoftware.
 14. The communications system of claim 12, wherein thesoftware architecture uses a client-server model.
 15. The communicationssystem of claim 12, wherein the software architecture includes a GUI.16. The communications system of claim 12, wherein the softwarearchitecture includes SQL functionality.
 17. The communications systemof claim 12, wherein the system services layer includes JAVAfunctionality.
 18. The communications system of claim 12, wherein thesystem services layer includes TCPJIP services.